A data transfer path from an originator network element to a destination network element may comprise multiple successive hops each being between two network elements located on the above-mentioned data transfer path and interconnected with a data transfer link that can be e.g. a copper wire link, a fiber link, or a radio link. These two network elements can be, for example, Ethernet switches operating on the Open System Interconnection “OSI” Level 2, i.e. on the “L2 data link layer”. The originator network element and the destination network element can be, for example, Internet Protocol “IP” routers operating, in addition to the L2 data link layer, on the Open System Interconnection “OSI” Level 3, i.e. on the “L3 network layer”. The data transfer speed available on each hop depends on the data transfer speed of the data transfer link being used and/or on other factors such as, for example, a transmitter shaper at the transmission-end of the hop under consideration and/or a receiver shaper at the reception-end of the said hop. Furthermore, one or more of the hops of the data transfer path may have dynamically changing data transfer speed. A hop having dynamically changing data transfer speed can be, for example, a hop implemented with an adaptive microwave “MW” Ethernet radio link whose data transfer speed is adapted according to weather conditions. The data transfer speed of an adaptive microwave Ethernet radio link may vary, for example, from 100 Mbits/sec to 500 Gbits/sec depending on weather conditions. Yet furthermore, buffering capacity available at a transmission-end of an adaptive microwave Ethernet radio link can be quite limited. The above-mentioned viewpoints complicate the control and the management of the end-to-end quality of service “QoS” provided by the data transfer path.
Publication US20120076029 describes a system where maintenance entities may be defined between customer and provider points to allow performance management to take place on an Ethernet network. The maintenance entities may be defined for access links, intra-domain, and inter-domain, and may be defined on a link or service basis. Performance parameters, including availability metrics, may be collected for the maintenance entities. Use of this system for controlling and managing the end-to-end quality of service “QoS” provided by data transfer paths of the kind described above is, however, complicated.